The present invention relates to radio frequency (RF) communication devices. In particular, the transmission and reception of wireless signals at different frequency bands. Portable devices such as laptop personal computers (PC), Personal Digital Assistant (PDA) and cellular phones with wireless communication capability are being developed in ever decreasing size for convenience of use. Correspondingly, the electrical components thereof must also decrease in size while still providing effective radio transmission performance. However, the substantially high transmission power associated with RF communication increases the difficulty of miniaturization of the transmission components.
A major component of a wireless communication device is the radio frequency power amplifier. The PA is conventionally in the form of a semiconductor integrated circuit (IC) chip or die in which signal amplification is effected with substantial power. The amplifier chip is interconnected in a circuit with certain off-chip components such as inductors, capacitors, resistors, and transmission lines used for controlling operation of the amplifier chip and providing impedance matching of the input and output RF signals. The amplifier chip and associated components are typically assembled, on a printed circuit board (PCB) in which the components are interconnected by layers printed metal circuits and layers of dielectric substrates.
Another desirable function for wireless communication devices is the capability to transmit and receive wireless signals at more than one frequency bands. The wireless communication devices need to switch between the reception mode and the transmission modes of operations. The wireless communication devices are also required to select signals from a plurality of different band frequencies and to receive or transmit signals at high signal-to-noise ratios.
There is a need to provide a wireless communication device that can fulfill the above functions and is also compact, simple and low cost.